Multiferroic behavior in trimerized Mott insulators

TL;DR

This paper demonstrates multiferroic behavior in trimerized Mott insulators, showing coexistence of ferroelectricity and magnetic orderings influenced by magnetic field and interlayer exchange, with abrupt polarization changes.

Contribution

It introduces a model of stacked triangular layers of trimers exhibiting multiferroic properties driven by spin-charge interplay in frustrated units.

Findings

Ferroelectric states coexist with magnetic orderings.

Electric polarization changes abruptly with magnetic field.

Multiferroic behavior depends on interlayer exchange sign.

Abstract

We demonstrate multiferroic behavior in trimerized Mott insulators through interplay between spins and electric dipole moments resulting from electronic charge fluctuations in frustrated units. The model consists of stacked triangular layers of trimers with small intertrimer exchange interactions $J'$ and $J"$. Ferroelectric states coexist with ferro- or antiferromagnetic orderings depending on the value of the magnetic field $H$ and the sign of the interlayer exchange $J"$. The electric polarization undergoes abrupt changes as a function of $H$.